On Thu, Apr 10, 2008 at 10:04 AM, Brian Granger <[EMAIL PROTECTED]> wrote: > > > > Lisandro Dalcin (author of mpi4py) came up with the following trick > > > that, while more complicated, prevents memory leaks: > > > > > > cdef extern from "Python.h": > > > object PyString_FromStringAndSize(char*,Py_ssize_t) > > > char* PyString_AS_STRING(object) > > > > > > cdef inline object pyalloc_i(int size, int **i): > > > if size < 0: size = 0 > > > cdef Py_ssize_t n = size * sizeof(int) > > > cdef object ob = PyString_FromStringAndSize(NULL, n) > > > i[0] = <int*> PyString_AS_STRING(ob) > > > return ob > > > > > > and now > > > > > > def foo(sequence): > > > cdef int size = len(sequence), > > > cdef int *buf = NULL > > > cdef object tmp = pyalloc_i(size, &buf) > > > > > > This could probably be adapted into a malloc-like function. What do > > > people think? > > > > Could you explain what the point is? Is it that this is a trick so that > > Cython will correctly garbage collect the allocated memory, even > > if an exception occurs? > > Yes, that is the idea. By having a python object that knows about the > memory, the garbage collection should prevent memory leaks if an > exception occurs. I am not sure if Lisandro has proved that this is > the case - he is just wondering how people typically handle this case. > > Seems like we are not alone in thinking this is a problem though. >
It's I think a general problem not only in Python but in programming in general. The authors of http://www.flintlib.org/ -- a pure C library -- spent a lot of time worrying about this, just to I think decide that it's a really hard problem. That said, there is definitely a significant class of problems in the context of Cython that could be fixed if Lisandro's suggestion works. Thanks for posting it! William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
